Mouse resolution for a computer mouse is measured in terms of counts per inch (CPI), which is also known interchangeably as dots per inch (DPI). CPI or DPI is a number of steps the mouse reports to the operating system (OS) when the mouse moves by one inch. This value varies from mouse to mouse within a great range, for example, from about 200 DPI to larger than 10000 DPI. To correctly map the mouse movement steps to the cursor movement on the screen, the OS uses the mouse DPI. However, the mouse does not report its DPI to the OS.
Instead, the OS may use a default mouse DPI or the OS may use an exhaustive DPI look-up table. In the first instance when the OS uses a default mouse DPI, the user is required to adjust the mouse speed setting if the user is not satisfied with the mouse performance, which may lead to an inferior user experience. In the second instance, developers (e.g., OS developers) may need to manually measure each different type of mouse to determine the DPI for the mouse to build the look-up table.